THE MECHANISM OF STABILIZATION OF HIGH-MAGNESIA PORTLAND CEMENTS BY REACTIVE SILICA UNDER AUTOCLAVE CONDITIONS.

FACTORS WHICH PLAY IMPORTANT ROLES IN THE MECHANISM OF STABILIZATION OF HIGH-MAGNESIA PORTLAND CEMENTS BY ACTIVE SILICATE MATERIALS UNDER AUTOCLAVE CONDITIONS HAVE BEEN CONSIDERED. AMONG THESE, REDUCTION IN THE RATE OF HYDRATION OF UNCOMBINED MAGNESIUM OXIDE, FORMATION OF A MAGNESIUM SILICATE HYDRATE SIMILAR TO THE NATURAL MINERAL DEWEYLITE AND DEVELOPMENT OF SUBSTANTIAL STRENGTH IN AUTOCLAVED PRODUCTS ARE THOUGHT TO BE THE PRINCIPAL FACTORS WHICH CONTROL THE VOLUME-EXPANSION OF THESE CEMENTS. IT IS PROPOSED THAT STRENGTH DEVELOPMENT IN THESE MATERIALS IS CONSEQUENT UPON THE FORMATION OF LARGE AMOUNTS OF THE WELL CRYSTALLIZED 11 ANGSTROM TOBERMORITE PHASE. THE EXTRA STRENGTH GENERATED IN AUTOCLAVED MIXTURES OF CEMENT WHEN THEY INCORPORATE ACTIVE SILICA MAY BE SUFFICIENT TO CONTAIN THE EXPANSIVE FORCES GENERATED BY THE HYDRATION OF PERICLASE INTO BRUCITE. MUCH MAGNESIUM HYDROXIDE, VERY LITTLE CALCIUM HYDROXIDE AND SOME UNHYDRATED MAGNESIUM OXIDE ARE PRESENT IN THE FINAL PRODUCTS IN ADDITION TO TOBERMORITE. SOME INFORMATION ON THE MICROSTRUCTURE OF THE STABILIZED CEMENT AS SEEN WITH A SCANNING ELECTRON-MICROSCOPE IS GIVEN. /A/RRL/

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00249831
• Supplemental Notes:
  • Vol 21, No 68, P 141-150, 3 FIG, 6 TAB, 7 PHOT, 24 REF
• Authors:
  • Majumdar, A J
  • Rehsi, S S
• Publication Date: 1969-9

Media Info

• Serial:
  • MAGAZINE OF CONCRETE RESEARCH
  • Publisher: Thomas Telford Limited
  • ISSN: 0024-9831

Subject/Index Terms

• TRT Terms: Calcium; Crystallization; Hydration; Hydroxides; Magnesium; Microstructure; Oxides; Portland cement; Silicates; Soil stabilization; Strength of materials; Tobermorite
• Uncontrolled Terms: Autoclaves; Stabilization
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00213100
• Record Type: Publication
• Source Agency: Road Research Laboratory /UK
• Files: TRIS
• Created Date: Sep 14 1970 12:00AM